BEIJING — The Chinese air force sent its mainstay Su-30 and J-11 fighters and an early-warning aircraft to patrol its air defense identification zone on Thursday, an air force spokesman told China’s state-run Xinhua news agency.

The spokesman said the air force “will make patrol flights within the zone standard practice,” but did not clarify whether Thursday’s patrol zone overlapped with those of Japan, South Korea and Taiwan.

The air force said it will remain on high alert and protect its air defense security “by taking measures commensurate with the level of threats.” The comment was apparently aimed at curtailing the repeated entry of U.S. and Japanese forces jets into the area without prior notice.

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